Conveyor

ABSTRACT

Disclosed herein is a conveyor structure having three pans which are in side-by-side relationship and each of which is movable fore and aft independent of the others. Rotating cam means are provided for moving each pan aft, letting each pan move forward, and stopping such forward movement relatively suddenly. By continued repeating of the rotation of the cam means, particles which fall on the pans are fed forwardly thereof, and onto a lateral pan which moves in a manner similar to the movement of any one of the three pans, but lateral to the direction of that movement.

United States Patent (72] Inventor DavidlLVanTuyl Palo Alto, Calif. [21] Appl. No. 760,254 [22] Filed Sept. 17, I968 [45] Patented [73] Assignee Jan. 26, 1971 Clemco-Clementina Ltd. San Francisco, Calif.

a general partnership [54] CONVEYOR 10 Claims, 16 Drawing Figs.

[52] US. Cl 198/82, 198/220. 209/339, 209/365 511 int. Cl 865g 37/00 [50] Field of Search ..l98/220(D20) 220KB); 209/255. 258, 259. 325,. 329. 339,- 365, 365.1: l98/220(D60). 220(C10), 220(Al0); 198/82 [56] References Cited UNITED STATES PATENTS 3,010,563 11/1961 Keegan l98/220X(Al0) 3,021,952 2/1962 Powell 209/339 3,097,734 7/1963 Erickson l98/220(A10)X 3,276,307 10/1966 Williamson ..l98/220(D60)X FOREIGN PATENTS 796,161 6/1954 Great Britain 198/220(Cl0) Primary Examiner-Gerald M. F orlenza Assistant Examiner-George F. Abraham Att0rneyMellin, Moore & Weissenberger ABSTRACT: Disclosed herein is a conveyor structure having three pans which are in side-by-side relationship and each of which is movable fore and aft independent of the others.

Rotating cam means are provided for moving each pan aft,

letting each pan move forward, and stopping such forward movement relatively suddenly. By continued repeating of the rotation of the cam means, particles which fall on the pans are fed forwardly thereof, and onto a lateral pan which moves in a manner similar to the movement of any one of the three pans, but lateral to the direction of that movement.

PATENTED JAN 26 I971 SHEET 1 OF 6 FlG 1 INVENTOR. DAVID H. VAN TUYL Map M ATTORNEYS PATENTEUJANZBIB?! 3557.936

' sum 2 or 6 ZZ/WC 5 Z FIG-.2

INVENTOR. DAVID H. VAN TUYL I m F I ATTORNEYS PATENTEDJANZBIQH 3557,9355

SHEET 3 [IF 6 FIG 7 INVENTOR. DAVID H. VAN TUYL m M P w ATTORNEYS PATENTEU m2 6 1971 SHEET 0F 6 I NV ENTOR DAVID H. VAN TUYL BY W kmwzu ATTORNEYS PATENIEDJAN26|91| SHEET 5 0F 6 U mmlLU Qw Or/ OH QE INVENTOR DAVID H. VAN TUYL ATTORNEYS CONVEYOR BACKGROUN D OF THE INV ENTION This invention relates to conveying structures, and, more particularly, to a conveyor in which pans are moved fore and aft for conveying particles thereon. I

Conveyors which use intermittent motion of a platform to move objects thercalong are well known. Generally, the platform is moved in one direction in a relatively slow manner, with an object thereon holding its position relative to the platform during this slow movement. Then the platform is moved relatively more rapidly in the opposite direction, carrying the object with it, and is stopped suddenly, whereby the object continues to move a certain distance after the platform has been suddenly stopped. Repetition of this motion moves the object to the end of the platform.

Platforms which describe such motion, it has been found, can be used under a grating which acts as the floor of a sandblast room. In such use, a pit is dug in the ground, and the complete mechanism is disposed therein. The sand used in blasting falls through the grating and onto the platform or platforms of the mechanism which convey the sand so that it may he recovered.

Heretofore, systems of this type, when used for recovery of sand in sandblasting operations, have revealed several serious drawbacks. First, all prior known systems are quite deep in dimension, and thus require the digging of a deep pit, resulting in great labor cost. Second, prior known systems are not suited to sandblasting operations because .they are not capable of sustaining the enormous weights (which may, for example, take the form of a railroad car on rails) which are sometimes involved in such operations. Third, all prior known systems have been designcd to provide rapid intermittent motion so that particles can be conveyed relatively rapidly. This is so because such a system is used generally when relatively highspeed conveying is required. This high-speed operation, as might well be expected, requires a degree of complication and refinement which spells high cost. Fourth, the known systems, not being designed for use in sandblasting operations, do not provide protection to the operating mechanism from the damage that can occur thereto by getting sand in undesirable places.

Mainly, these problems result from the fact that, while it is possible to apply known conveying systems of this type to sandblasting operations, such known systems were not designed with sandblasting in mind.

It is therefore an object of this invention to provide a conveying system of the fore-and-aft motion type which is of relatively small overall depth, meanwhile being quite effective in use as a sand recovery system in sandblasting.

It is a further object of this invention to provide a system which, while fulfilling the above objects, is capable of sustaining relatively great work loads in such use without any special reinforcement.

It is a still further object of this invention to provide a conveying system which may be built in modular form to adapt to various space requirements.

It is a still further object of this invention to provide a system which, while fulfilling the above object, is extremely simple and relatively inexpensive, requiring a minimum of parts, and a minimum of power to operate it, and has extremely low maintenance requirements.

SUMMARY OF THE INVENTION Broadly stated, applicant's apparatus for conveying particles or the like comprises a frame, and a substantially horizontal pan associated with the frame and on which the particles are received. Linkage means interconnect the pan and the frame, whereby the pan is supported by the frame, the linkage means allowing the pan to be swung in a first direction relative to the frame and in a second direction opposite the first direction relative to the frame. Repeating means are included for repeatedly (i) moving the pan in the first direction relative to the frame, the pan carrying the particles therewith in the first direction; (ii) allowing the pan to move under its own weight in the second direction relative to the frame, the pan carrying the particles therewith in the second direction, and (iii) stopping the pan movement in the second direction relatively suddenly, whereby the particles on the pan are moved a certain distance in the second direction relative to the pan.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects of the invention will become apparent from a study of the following specification and drawings, in which:

FIG. I is a plan view of the preferred embodiment of the system;

FIG. 2 is a view taken along the line 2-2 of FIG. 2;

FIG. 3 is a view similar to FIG. I but further along in rotation of the cam shown therein;

FIG. 4 is a view taken along the line 4-4 of FIG. 3;

FIG. 5 is a sectional view taken along the line 5-5 of FIG. 1;

FIG. 6 is a sectional view, with portions removed, taken along the line 6-6 of FIG. I;

FIG. 7 is a sectional view taken along the line 7-7 of FIG. I;

FIG. 8 is a view, with portions removed, taken along the line 8-8ofFIG. l; i

FIG. 9 is a view similar to FIG. 8, but further along in the rotation of the cam shown therein;

FIGS. I0-I2 are schematic plan views of the device, showing the sequential operation of the plans thereof;

FIG. 13 is a plan view of another embodiment of the cross conveyor of the system;

FIG. I4 is a view taken along the line 14-14 of FIG. 13;

FIG. 15 is a plan view of another embodiment of means for moving the pans of the system;

FIG. 16 is a view taken along the line 16-16 of FIG. 15.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Shown generally at 10 in FIG. 1 is a conveyor. The conveyor 10 includes parallel longitudinal rails 12, I4, 16 and I8, and end rails 20 and 22 joining rails 12, I4, 16 and 18 at the ends thereof. Set parallel to and adjacent the rails 22 is a rail 24, fixed to rail 22 by interconnecting braces 26, 28, 30, 32. The rails l2, l4, 16, 18,20, 22, 24 and braces 26, 28, 30, 32 make up a conveyor frame 34. Set between the rails 22, 24 is the conveyor-actuating mechanism 36, which will later be described in detail.

A first substantially horizontal pan 38 is disposed between rails I2, I4, a second substantially horizontal pan 40 is disposed between rails l4, l6, and a third substantially horizontal pan 42 is disposed between rails I6, 18. These pans 38, 40, 42 are aligned in side-by-side relation, and are associated with the frame 34 by means best shown in FIGS. 5 and 6.

As shown therein, rail I6 is made up of two parts and is I- shaped in cross section. Extending from opposite sides of rail 16 and fixed thereto are blocks 44, 46, from which are pivotally hung links 48, 50, respectively. Pivotally attached to link 48 is a bar 52 on which pan 40 is bolted. Pivotally attached to link 50 is a bar 54 on which pan 42 is bolted. It will be understood, of course, that bars 52, 54 extend to similar structures which link them in the same manner with rails I4, I8, respectively.

Further along the rail 16 is a block 56 which extends therefrom, from which is pivotally hung a link 58 (FIG. 6). A bar 60 is pivotally attached to link 58, and a pan 42 is bolteld thereon. It will be understood, of course, that bar 60 extends to similar structure which links it in the same manner with rail I8. The linkage means associated with pan 42 is repeated for the other pans 38, 40. Part 38 is thus supported by linkage means to rails I2, I4, pan 40 is supported by linkage means to rails I4, 16, and pan 42 is supported by linkage means to rails 16, I8.

As shown in FIG, 6. these linkages support the pans and allow each pan (as pan 42) to be swung in a first direction relative to the frame 34 and a second direction opposite that first direction relative to frame 34. Furthermore, it will be seen that, because of such structure, each pan is movable in such manner (i.e., back and forth) independent of the other pans. The pans 38, 40, 42 are reinforced and stiffened by longitudinal brackets 62, 64, 66 fixed thereto respectively (Fig. 1).

As shown in FIG. 5, a substantially flat resilient member 68 overlies rail 16. One edge 68A ofthe member 68 extends over the pan 40, and the other edge 68B of the member 68 extends over the pan 42. Barrier members 70, 71 extend from the pan 40, and the extended edge 68A is disposed between them. Barrier members 72, 73 extend upward from pan 42. and the extended edge 68B is disposed between them. Such member 68 allows the back-andaorth movement of the pans 40, 42 described above. Similar members 74, 76, 78 are provided (FIG. 1) with proper accompanying structure where needed. These resilient members serve as effective seals in a manner which will be described later.

As shown in FIG. 6, pan 42 ends in an upper lip portion 428, which is disposed in an opening 21 in the inward portion A of rail 20. A resilient member 77 runs along the lip por tion 428 for its full width and is positioned to and interconnects the lip portion 428 and the inward portion 20A. Such resilient member 77 is sufficiently resilient and wide to allow the back-and-forth movement of pan 42. Similar members (not shown) are associated with pans 38 and 40. These resilient members, as will later be explained, act as effective seals.

Disposed between rails 22, 24 is a pan 80, which is disposed substantially horizontally. This pan 80, as best shown in FIGS. 8 and 9, is supported by linkages 82, 84 fixed to the frame 34, similar to the linkage means describedpreviously. These linkages allow the pan 80 to be swung back and forth in directions lateral to the direction of swing of the pans 38, 40, 42 (FIG. 1). This swing of pan 80 is shown in FIGS. 8 and 9. The ends 40A and 42A of pans 40, 42 extend through openings 86, 88 respectively in rail 22 (FIG. 5) and over the pan 80 (FIGS. 1 and 2). Similarly, the end of pan 38 extends through an opening in rail 22 and over the pan 80.

The conveyor-actuating mechanism 36 is actually a rotating cam means which includes a longitudinal shaft 90 rotatably supported on braces 26, 28, 30, 32. The shaft 90 has mounted therealong substantially flat cam members 92, 94, 96, which operate on pans 38, 40, 42 respectively in a similar manner. Consequently, only the structure associated with cam member 94 will be described in detail (FIGS. 2-4 and 7).

The outer surface 98 of cam member 94 defines a camming surface, as do the outer peripheries of cam members 92 and 96. Extending from rails 22, 24 respectively are support bars 100, 102. Supported on either side of cam member 94, by pivotal link bars 104, 106 which connect to support bars 100, 102 respectively, are plates 108, 110. Rotatably suspended by and between the plates 108, 110 is a roller 112, on which bears the camming surface 98 of cam member 94. Extending from a pin 114 interconnecting plates 108, 110 is a flat bar 116. Pivotally interconnecting the flat bar 116 and longitudinal bracket 64 is a connecting link 118. With rotation of the shaft 90, it will be seen that the camming surface 98 of cam member 94, bearing on roller 112, transfers motion to pan 40.

If cam member 94 is rotated in the direction shown by the arrow in FIG. 2, it will be seen that, because of the shape of camming surface 98, the pan 40 will be moved to the left relatively gradually, and also slightly upward through the pivoting of the linkages supporting the pan 40. When the cam member 94 rotates sufficiently to have point 98A of the camming surface 98 in contact with roller 112, the pan 40 then starts to move to the right and downward (FIG. 3) under its own weight (by means of the pivotal linkages supporting the pan 40) relatively more suddenly than it was moved to the left. As the camming member 94 rotation continues, the pan 40 reaches the end of its travel to the right. and is stopped rather suddenly by the plates I06, 108 striking a rubber bumper or stop 99 fixed to rail 24. This rotation, of course, may be continued indefinitely. The pans 38, 42 have similar camming structure associated therewith. and move in the same way as pan 40. However, equivalent movement for the pans 38, 40. 42 takes place l20 apart. This will be described more fully further on.

Fixed to the shaft 90 is a circular cam member 120 (FIGS. 8 and 9). A side 122 of the circular cam members 120 defines a camming surface which is positioned to bear on a roller 124 fixed to pan 80. Rotation of shaft 90. it is seen, rotates circular cam member 120, transferring motion to pan through roller 124.

As circular cam member 120 is rotated, it is configured to move the pan 80 to the left and slightly upward (through the linkages supporting the pan 80) (FIG. 8) relatively gradually. When the circular cam member 120 is rotated sufficiently, the pan 80, under its own weight (through the linkages supporting it), will move to the right and downward relatively more suddenly than it was moved to the left. As rotation of the circular camming member 120 continues, the pan 80 reaches the end of its travel to the right, and is stopped relatively suddenly by the configuration of the camming surface 122 of circular camming member 120, or by a stop (not shown) similar to stop 99. This rotation, of course, may be continued indefinitely.

The operation of the device is best understood with reference to FIGS. 10--l2. Therein is shown a schematic plan representation of the pans 38, 40, 42, 80 and camming members 92, 94, 96 and 120 which define their respective motions. If the device is to be used in conjunction with sandblasting, a grating 101 (FIG. 5) is positioned on the frame 34 over the conveyor 10. The grating acts as a floor on which workmen can walk. Such a grating, of course, allows free movement of the pans 38, 40, 42, 80.

In such an operation, the shaft is rotated by means not shown. Sand used in the sandblast room falls through the grating 101 and onto platforms 38, 40, 42.

In FIG. 10, pan 40 is being moved as indicated by the arrow thereon relatively gradually, carrying the granules of sand thereon with it as it moves. In FIG. 11, pan 40 has reached the maximum of its movement in that direction, and as the camming member 94 continues to rotate, the pan 40 moves under its own weight in a direction opposite the direction it originally moved, indicated by the arrow in FIG. 11, relatively more suddenly than it moved in the first direction, carrying the particles of sand with it. The pan 40 movement is then suddenly stopped by the stop 99 (FIG. 12). With the sudden stop, the particles on pan 40 continue moving a certain distance relative to the pan and toward pan 80 through their own momentum. Continued rotation of shaft 90, of course, will move the particles on pan 40 to its end. The pans 38, 42 describe exactly the same motion. However, as a study of FIGS. 10-12 reveals, they are out of phase. This means that the conveyor 10 operates in a quite smooth manner and requires a minimum of power to turn shaft 90.

The pan 80 is positioned to receive sand particles which fall off pans 38, 40, 42. The pan 80, as also shown in FIGS. l0- l2, is moved to the right and raised slightly through the linkages supporting it (FIG. 10) relatively gradually with rotation of the camming member 120, the pan 80 carrying the sand particles thereon with it. The pan then moves under its own weight downward and to the left (FIG. 11) relatively more suddenly, carrying the particles thereon with it as it so moves. The pan 80 is then stopped suddenly (FIG. 12). With the sudden stop, the particles on pan 80 continue to move a certain distance, through their own momentum, relative to pan 80. Because of the position of pan 80, the particles fed thereinto from pans 38, 40, 42 may be conveyed laterally of the direction of feeding of the particles, and to a point where they may be recovered and, of course, reused.

It will be understood that, in a sandblasting operation, the sand will fall rather indiscriminately about the working area. It will be understood also that if sand is allowed into the area of the linkages or of the operating mechanism, relatively great wear or perhaps severe damage thereto can occur. Members such as 68, 77 prevent such wear and damage.

As seen in FIG. 5, barrier members 70, 72 have portions 70A, 72A which angle inwardly toward rail 16 and over edges 68A, 68B of member 68. Sand falling through grating 101 and onto these angled portions 70A, 72A will be fed thereby onto pans 40, 42 and conveyed thereon. Sand which falls through grating 101 inward of the angled portions 70A, 72A will fall directly on resilient member 68 and slide down it to edges 68A, 68B. The sand falling off edge 68A is received on the pan 40 between barrier members 70, 71, and the sand falling off edge 68B is received on the pan 42 between barrier members 72, 73. Such sand falling in these areas is conveyed therealong in the same manner as the sand on the main portions of the pans 40, 42. In any case, sand in these areas is kept to a minimum by barrier members 70A, 72A. And, very importantly, no sand can fall into the areas inward of barrier members 71, 73, where the linkages are situated. In combination with resilient members such as 77, members such as 68 allow the pans 38, 40, 42 to describe the motion necessary to convey sand particles thereon. Meanwhile, they provide an extremely effective seal between the pans 38, 40, 42 and the framework 34, so that no damage can occur to the linkage structure and operating mechanism of the device.

To further effectuate proper sealing, the resilient member 68 may be fixed to the barrier members 71, 73, the resiliency of member 68 being such as to allow the movement of the pans 40, 42 as described above.

It will be seen that a screw conveyor mechanism 130 can be used in place of the pan 80 and its associated structure. Such a substitution is shown in FIGS. 13 and 14. As shown therein, pans 38, 40, 42, operated by earns 92, 94, 96 as previously described, are positioned to feed sand conveyed thereby into a trough 132 which runs along and between rails 22, 24. A screw 134, on a rotatable shaft 136, feeds sand in the trough 132 to the end thereof, where it may be recovered.

It will further be understood that other embodiments of cross-conveyors may he used in place of the pan 80 or screw conveyor mechanism 130. For example, sand may be fed from pans 38, 40, 42 into a lateral duct (not shown) and moved by pressure or suction means which force air through the lateral duct, such air carrying the sand therewith to the end of the duct, where it may be recovered.

As shown in FIGS. and 16, hydraulic cylinders 140, 142, 144 may be used in place of the earns 92, 94, 96 and associated structure to move the pans 38, 40, 42. Each of these cylinders 140, 142, 144 is pivotally fixed to the rail 24, and has its piston rod fixed to one of the pans 38, 40, 42. Suitable hydraulic actuating means (not shown). may be connected to each cylinder 140, 142, 144 so that proper motion of the pans 38, 40, 42 is achieved. Such hydraulic cylinder means can be used in combination with a screw conveyor structure 130 as shown in FIGS. 13 and 14, or in combination with the pan 80 and associated structure previously described.

It will be understood that, in all those instances where linkages are used to support the pans and allow movement thereof, equivalent means could be substituted therefor. For example, pans such as 40 could be movable back and forth on rollers, and spring means could be provided, with the cams moving the pans against the spring force and then allowing the springs to move them back.

It will be understood that the pans may be of any width, length, or number, and that the overall size of the system may vary. The system itself, it will be seen, may be built in modular form to adapt to various space requirements.

The system disclosed herein is designed mainly for lowspeed operation, which is all that is required in the recovery of sand particles in sandblasting. Thus, a minimum of power need be supplied to shaft 90, since it need not be rotated rapidly. Power requirements are further minimized because of applicants use of l2()-out-of-phase operation of the pans 38, 40, 42 as described above.

It is to be noted with great importance that the entire conveyor 10 is quite shallow in overall dimension. This means that only a very shallow pit need be dug, resulting in great savings of time and labor. Alternately, the shallow conveyor 10 may be placed directly on the ground, with no pit at all, and a ramp run up to it.

The overall system is capable of sustaining extremely great weight. For example, tracks on which railroad cars may run may be placed on rails such as 16 (FIG. 5) which are capable of supporting such a load.

It will be seen that the overall device is quite simple, and has been found to be quite efficient in operation. Maintenance is not a problem, since all parts are quite strong, and the cam drive means and structure associated therewith are protected by their positioning from sand particles, which could cause excessive wear and damage. The rubber members. as 68, 77, act to protect the device from wear, as previously explained.

I claim:

1. Apparatus for conveying particles or the like comprising:

a. a frame;

b. a substantially horizontal pan associated with the frame and on which the particles are received;

c. linkage means interconnecting the pan and the frame, whereby the pan is supported by the frame, the linkage means allowing the pan to be swung in a first direction relative to the frame and in a second direction opposite the first direction relative to the frame; and

d. repeating means for repeatedly i. moving the pan in the first direction relative to the frame, the pan carrying the particles therewith in the first direction;

ii. allowing the pan to move under its own weight in the second direction relative to the frame, the pan carrying the particles therewith in the second direction; and

iii. stopping the pan movement in the second direction relatively suddenly, whereby the particles on the pan are moved a certain distance in the second direction relative to the pan.

2. Apparatus according to claim 1 wherein the repeating means comprises rotating cam means associated with the frame for moving the pan in the first direction relative to the frame, and stop means fixed to the frame for stopping the pan movement in the second direction relative to the frame.

3. Apparatus according to claim 2 wherein the rotating cam means comprises a rotating shaft mounted to the frame and a substantially fiat cam member fixed to the shaft, the outer periphery of the substantially flat cam member defining a camming surface.

4. Apparatus according to claim 3 wherein is included conveyor means positioned to receive particles which fall off the pan after being moved relative to the pan to an edge thereof during a plurality of rotations of the cam means, the conveyor means further being positioned to convey particles laterally of the movement of the particles in the second direction.

5. Apparatus according to claim 4 wherein the conveyor means comprises a second substantially horizontal pan associated with the frame and on which particles are received from the first-mentioned pan, second linkage means interconnecting the second pan and the frame, whereby the second pan is supported by the frame, the second linkage means al lowing the second pan to be swung in a third direction relative to the frame and in a fourth direction opposite the third direction relative to the frame, with the swing of the first pan in the second direction; and second rotating cam means adapted with each rotation to i. move the second pan in the third direction relative to the frame, the second pan carrying the particles therewith in the third direction;

ii. allow the second pan to move under its own weight in the fourth direction relative to the frame, the second pan carrying the particles therewith in the fourth direction; and

iii. stop the second pan movement in the fourth direction relatively suddenly, whereby the particles on the second pan are moved a certain distance in the fourth direction relative to the second pan with each rotation of the second cam means.

6. Apparatus according to claim wherein the second rotat ing cam means comprises a circular cam member fixed to the shaft, a side of the circular cam member defining a camming surface.

7. Apparatus according to claim 4 wherein the conveyor means comprises a screw conveyor associated with the frame.

8. in a conveyor having a frame including a plurality of longitudinal members. a plurality of end members interconnect ing the longitudinal members, and a conveying platform movable along and relative to the longitudinal members, sealing means associated with a longitudinal member for keeping particles or the like deposited on the conveyor from falling between that longitudinal member and the conveying platform comprising:

a. a substantially flat, resilient member overlying the lon gitudinal frame member and extending therefrom over the conveying platform; and

b. means for holding the extension of the substantially flat resilient member over the conveying platform comprising first and second barrier members extending from the conveying platform and between which the extension of the substantially flat resilient member fits in slidable relation thereto.

9. A conveyor according to claim 8 wherein the resilient member is fixed tothe barrier member most adjacent the longitudinal frame member.

10. A conveyor according to claim 9 wherein the conveying platforms moves toward and away from an end member of the frame to convey particles or the like thereon. and further in cluding a resilient member running along and interconnecting that end member and the conveying platform and allowing such movement. 

1. Apparatus for conveying particles or the like comprising: a. a frame; b. a substantially horizontal pan associated with the frame and on which the particles are received; c. linkage means interconnecting the pan and the frame, whereby the pan is supported by the frame, the linkage means allowing the pan to be swung in a first direction relative to the frame and in a second direction opposite the first direction relative to the frame; and d. repeating means for repeatedly i. moving the pan in the first direction relative to the frame, the pan carrying the particles therewith in the first direction; ii. allowing the pan to move under its own weight in the second direction relative to the frame, the pan carrying the particles therewith in the second direction; and iii. stopping the pan movement in the second direction relatively suddenly, whereby the particles on the pan are moved a certain distance in the second direction relative to the pan.
 2. Apparatus according to claim 1 wherein the repeating means comprises rotating cam means associated with the frame for moving the pan in the first direction relative to the frame, And stop means fixed to the frame for stopping the pan movement in the second direction relative to the frame.
 3. Apparatus according to claim 2 wherein the rotating cam means comprises a rotating shaft mounted to the frame and a substantially flat cam member fixed to the shaft, the outer periphery of the substantially flat cam member defining a camming surface.
 4. Apparatus according to claim 3 wherein is included conveyor means positioned to receive particles which fall off the pan after being moved relative to the pan to an edge thereof during a plurality of rotations of the cam means, the conveyor means further being positioned to convey particles laterally of the movement of the particles in the second direction.
 5. Apparatus according to claim 4 wherein the conveyor means comprises a second substantially horizontal pan associated with the frame and on which particles are received from the first-mentioned pan, second linkage means interconnecting the second pan and the frame, whereby the second pan is supported by the frame, the second linkage means allowing the second pan to be swung in a third direction relative to the frame and in a fourth direction opposite the third direction relative to the frame, with the swing of the first pan in the second direction; and second rotating cam means adapted with each rotation to i. move the second pan in the third direction relative to the frame, the second pan carrying the particles therewith in the third direction; ii. allow the second pan to move under its own weight in the fourth direction relative to the frame, the second pan carrying the particles therewith in the fourth direction; and iii. stop the second pan movement in the fourth direction relatively suddenly, whereby the particles on the second pan are moved a certain distance in the fourth direction relative to the second pan with each rotation of the second cam means.
 6. Apparatus according to claim 5 wherein the second rotating cam means comprises a circular cam member fixed to the shaft, a side of the circular cam member defining a camming surface.
 7. Apparatus according to claim 4 wherein the conveyor means comprises a screw conveyor associated with the frame.
 8. In a conveyor having a frame including a plurality of longitudinal members, a plurality of end members interconnecting the longitudinal members, and a conveying platform movable along and relative to the longitudinal members, sealing means associated with a longitudinal member for keeping particles or the like deposited on the conveyor from falling between that longitudinal member and the conveying platform comprising: a. a substantially flat, resilient member overlying the longitudinal frame member and extending therefrom over the conveying platform; and b. means for holding the extension of the substantially flat resilient member over the conveying platform comprising first and second barrier members extending from the conveying platform and between which the extension of the substantially flat resilient member fits in slidable relation thereto.
 9. A conveyor according to claim 8 wherein the resilient member is fixed to the barrier member most adjacent the longitudinal frame member.
 10. A conveyor according to claim 9 wherein the conveying platforms moves toward and away from an end member of the frame to convey particles or the like thereon, and further including a resilient member running along and interconnecting that end member and the conveying platform and allowing such movement. 